Does your garden include some plants that produce autumn colour? Scientists still don’t know why trees change leaf colour in Autumn but the annual show of changing leaf colours is nonetheless a delight to witness.
When October comes around each year, especially in Northeastern North America, I am always in awe of the natural beauty of the trees as they turn from their summer green into a myriad of intense bursts of fiery flames of colour. This wonderful feature of deciduous trees can add interest and beauty to any garden and so it’s always a good idea to include some plants in your garden that produce autumn colour. Symbolically, the glorious colour show of changing leaf colour that Mother Nature provides to us in autumn is a reminder that aging can and is a beautiful part of life and natural cycles of change all have an underlying unique beauty and purpose.
So, what is the reason for changing leaf colour? Scientists have worked hard to understand this question and still don’t have all the answers but they do know enough to explain the basics. The timing of colour change and leaf fall is regulated by shorter days and other environmental influences such as temperature, rainfall and food supply. As days get shorter, and nights get longer and cooler, biochemical processes in the leaf begin to occur that affects leaf pigmentation.
Chlorophyll, which gives leaves their basic green colour is destroyed. This unmasks the remaining pigments that are present in the leaf to show their colours; Carotenoids, which produce yellow, orange and brown colours and Anthocyanins, which give red colouration.
The color of an autumn leaf can actually take a lot of work. In the fall, the green chlorophyll in a tree fades away, while the tree actively builds new pigments to turn it red or yellow. Most scientists agree that these colors must serve some function for trees. Otherwise, natural selection would favor drab trees that dropped their leaves without such bother. And trees could use the energy they didn’t waste on autumn colors to fight diseases, capture more sunlight, or some other essential task. However, we are still left with the mystery of autumn colours; which is fine with me. I still enjoy ruminating on the thought that nature is reminding me that the autumn of our lives can be glorious, vibrant and amazing.